#pragma GCC optimize("Ofast") #pragma GCC target("avx2") #define rd_init() char*rp=({char*mmap();mmap(0l,1l<<25,1,2,0,0ll);}) #define rd() ({int _v=0,_c;while(_c=*rp++-48,_c>=0)_v=_v*10+_c;_v;}) #define wt(v) ({ulong _z=v;do*--wp=_z%10+48;while(_z/=10);}) #define wt1(v) ({char wbuf[64],*wp=wbuf+sizeof wbuf;wt(v);write(1,wp,wbuf+sizeof wbuf-wp);}) #define rep(v,e) for(typeof(e) v=0;v<e;++v) #define MD 998244353 typedef unsigned long ulong; unsigned p2[]={2,4,16,256,65536,301989884,932051910,299560064,169907034,60241440,595200811,819041188,954185916,830057642,679814667,167578608,683753077,918327899/*,24717300*/,0}; int main(){ rd_init(); int n=rd(); unsigned __int128 a=0; rep(i,n){ a+=(ulong)(i+2)*(n+1-i)*rd(); } ulong v=a*873463809%MD; rep(i,18){ if(n&1<<i){ v=v*p2[i]%MD; } } wt1(v); _exit(0); }